How an Ocean Moves

Living in the ocean is very different to living on land. Ocean plants and animals have special ways of breathing, eating, moving, and keeping safe.

The blue whale is the biggest animal in the world. It can be more than

30 meters Long! It moves well in the ocean because the water holds it up.

+ Go to pages 24-25 for activities. •

In the ocean there are lots of very small animals and plants called plankton. The plankton live near the top of the ocean because they need sunlight. Small fish eat plankton. Big animals eat the small fish. Then even bigger animals eat them! So plankton are important for almost every ocean animal. This is called a food chain.

Animals that eat other animals are called predators. The animals that they eat are called prey. Most sharks are predators.

Sharks can swim very fast to catch their prey.

The whale shark is the biggest fish in the world. It's as

Long as a bus. It has no teeth, so it

only eats plankton and small shrimps':

Lots of seaweed called kelp grows near the seashore. The kelp is a safe home for many fish. Sea urchins eat kelp, and sea otters eat a lot of sea urchins. So sea otters help to keep enough kelp in the ocean for the fish to live in.

There's a lot of ocean life near the seashore because the water here is full of food. Many birds, fish, and shellfish live and feed near the seashore. The seashore is not always a safe place. Big waves can throw animals onto rocks or carry them away. At low tide, animals and plants can easily dry out in

the sun.

Limpets are animals that have a special strong foot that holds onto rocks. This keeps them safe from big waves. They also have a hard shell so they don't dry out.

Most trees can't live in salty ocean water, but mangrove trees grow on the seashore in tropical places. They have special roots so they can live in salt water. Many fish and other animals live under the roots of mangrove trees.

Under the water, sea anemones use their long tentacles to catch food

and to sting their predators.

At low tide, they pull their tentacles in so

they don't dry out.

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A mammal is an animal that drinks milk from its mother and breathes air. Most mammals, like people and elephants, live on land. Some mammals live in the ocean.

Because they feed and move in water, ocean mammals are different from land mammals 1n many ways.

The sea lion's body has a shape like a fish, so it can swim very fast. It doesn't have front legs, but it has flippers that pull it through the water.

Whales are ocean mammals. Like all whales, the sperm whale breathes through

a hole on its head called a blowhole. Sperm whales can stay underwater for two hours, and they can dive a long way down into

the ocean.

Some birds live, feed, and sleep on the ocean. They catch fish by diving under the water. Some birds only come to the seashore to make nests and to lay eggs.

----- The albatross has bigger wings than any other bird.

The two wings can be more than 3 meters wide! The albatross can fly up to 1,000 kilometers a day.

+ Go to pages 30-31 for activities.

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Clownfish live near

. the tentacles of sea anemones. Predators don't come near because

the tentacles can sting them.

The clownfish are safe because they have a special skin. Predators don't come near

lionfish either. The spines of a lionfish can

sting a fish and stop it moving, or even kill it.

Small fish called cleaner wrasse work hard on coral reefs. They eat the little plants and animals that live on big fish. Big fish don't eat the cleaner wrasse. They open their mouths so the wrasse can clean inside!

Corals are small animals that make hard covers around themselves. The covers are many different shapes and colors. Coral reefs are places where lots of corals live together. They are beautiful underwater worlds.

Many different plants and animals live on coral reefs. Coral reef.fish are very colorful so they are camouflaged - it's not easy to see them near the coral.

Small fish and other animals have to keep safe from predators. Some fish swim together in big groups called shoals. In a shoal, there are more fish to look out for predators. There are also lots of fish to eat. So if a fish is lucky, the predator eats one of the other fish!

The leafy sea dragon is very well camouflaged. When it hides in seaweed, other fish can't see it. Can you see this leafy sea dragon?

Octopuses camouflage themselves by turning a different color. Can you see this octopus? When an octopus is scared, it can also make a big cloud of black ink. This surprises predators and gives the octopus time to swim away.

When the porcupine fish sees a predator, it drinks lots of

water. This makes its body big and round like a ball, and its spines stand up. Predators

know that they can't eat

it so they don't come near.

+ Go to pages 34-35 for activities.. fl

A Jellyfish

A Hammerhead Shark

Big predators are very good at catching their prey. Sharks can smell and see very well. The hammerhead shark has nostrils and eyes at the ends of its head, so it can see and smell all around.

The electric ray can give other fish an electric shock. This stops them moving, or kills them, so that the ray can eat them.

Electric rays make electricity. Some make enough electricity to work a television!

All jellyfish have tentacles that can sting. When a fish swims near a jellyfish, the tentacles sting it many times. The jellyfish can then eat the fish.

The angler fish lives in deep water, where it's very dark and cold, but it has a small light on its head. When small fish see

the light, they think it's something that they can eat.

When they swim near, the angler fish eats them.

+ Go to pages 36-37 for activities.

Large parts of the Arctic Ocean and Southern Ocean have ice on them in winter.

There are also big icebergs. In summer, a

lot of the ice melts. Then there are little pieces of ice in the oceans, and the icebergs are smaller.

Polar bears live in the Arctic. Most of the year, they live on ice. They catch seals from holes in the ice. They also swim between the ice and icebergs. Polar bears are the biggest type of bear, but their cubs are very, very small when they are born.

In summer, the Southern Ocean has a lot of plankton. Many dolphins, whales, seals, and birds come there to feed.

Penguins live near the South Pole. They dive into the ocean for fish and other small animals. They have special feathers that

keep them warm and dry. Their feathers are so warm that penguins can sometimes get too hot!

Дата добавления: 2015-10-23